[Ips-dsgr] ASWFC Daily Report - 18 August 25 issued 2330 UT on 18 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Aug 19 09:30:49 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 AUGUST AND FORECAST FOR 19 AUGUST - 21 AUGUST
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 18 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Aug: 114/65
1B. SOLAR FORECAST
19 Aug 20 Aug 21 Aug
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 112/63 108/58 110/60
COMMENT: Solar activity on UT day 18-Aug was at the R0 level,
with no significant flaring activity. There are currently four
numbered sunspot regions visible on the solar disk. AR4187 (S21E24,
alpha) has developed over the UT day and newly numbered AR4188
(S10E72, alpha) has recently rotated onto the visible solar disk.
All other sunspot regions are either stable or in decay. Solar
activity is expected to be at the R0 level over 19-21 Aug. S0
solar proton conditions were observed on UT day 18-Aug. S0 solar
proton conditions are expected over 19-21 Aug. No Earth-directed
CMEs have been observed. The solar wind speed on UT day 18-Aug
increased, ranging from 290 to 390 km/s and is currently near
360 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 12 nT and the north-south IMF component (Bz) range
was -7 to +5 nT. The solar wind speed is expected to increase
over 19-Aug and remain elevated over 20-Aug due to coronal hole
high speed wind stream effects from an equatorial coronal hole
and may decline over 21-Aug.
-----------------------------------------------------------
2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Aug: G0
Estimated Indices 18 Aug : A K
Australian Region 4 01122212
Cocos Island 4 02112211
Darwin 5 12122212
Townsville 5 11122212
Learmonth 5 01122222
Alice Springs 4 01022212
Gingin 4 01112222
Canberra 2 00022111
Kennaook Cape Grim 3 10022112
Hobart 3 00022112
Estimated Antarctic Regional K Indices 18 Aug :
Macquarie Island 6 00043211
Casey 5 12222121
Mawson 5 01212312
Observed Regional daily pc3 Indices 18 Aug :
Darwin 2 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 3 (Quiet)
Hobart 10 (Quiet)
Pc3 pulsations are high frequency (10-45 second period) variations
of the Earths magnetic field. Daily pc3-indices are the daily sum
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data.
NOTE: Indices may have been generated from data obtained in
cooperation with the following organisations: Geoscience Australia,
University of Newcastle Space Physics Group, Australian Government
Antarctic Division and International Center for Space Weather
Science and Education, Japan.
Estimated AFr/Ap Indices 18 Aug : A
Fredericksburg 8
Planetary 10
Observed AFr/Ap Indices 17 Aug : A K
Fredericksburg 5
Planetary 5 1122 2100
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Aug 16 G0-G1
20 Aug 16 G0-G1
21 Aug 10 G0, chance G1
COMMENT: ASWFC Geomagnetic Warning 60 was issued on 17 August
and is current for 18-19 Aug. G0 geomagnetic conditions were
observed in the Australian and Antarctic regions on UT day 18-Aug.
G0-G1 geomagnetic conditions are expected over 19-20 Aug and
G0, chance of G1 over 21-Aug due to coronal hole high speed wind
stream effects from an equatorial coronal hole.
-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Aug Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Aug Normal Normal-fair Fair
20 Aug Normal Normal-fair Fair
21 Aug Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 18-Aug were
mostly normal, with periods of fair conditions at high latitudes.
HF radio propagation conditions are expected to be mostly normal
over 19-21 Aug, with fair conditions at high latitudes over 19-20
Aug due to expected geomagnetic activity.
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Aug 93
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 30% during local night.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 35% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Jul 88
Aug 96
Sep 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Aug 90 Near predicted monthly values
20 Aug 80 Near predicted monthly values
21 Aug 85 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 18-Aug were mostly near predicted monthly values.
Spread F was observed at Hobart and Perth during local night
hours. MUFs are expected to be near predicted monthly values
over 19-21 Aug.
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Aug
Daily Proton Fluence >1 MeV: 3.6E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 2.70E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:18%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.7
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Aug
Speed: 322 km/sec Density: 3.4 p/cc Temp: 35300 K Bz: 4 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------
Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
More information about the ips-dsgr
mailing list